More water from sewerage as dams dry up

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The proportion of WA’s water sourced from recycled sewerage has reached record levels while the amount taken from dams has plummeted to less than 30 per cent, an annual report shows.

The volume of recycled water supplied to Perth increased 21 per cent during 2010-11, accounting for more than 43 per cent of the state’s total.

Recycled water now accounts for 3 per cent of the state’s total water supply, according to an Economic Regulation Authority performance report on water and sewerage suppliers.

Recycled water is currently only used for non-drinking purposes while Water Corporation carries out a two-year trial ahead of its planned inclusion in the main household supply from December.

Environment Minister Bill Marmion has said he wants recycled water to be pumped into the main supply on a permanent basis as soon as possible

A Water Corporation survey showed earlier this year that more people supported the idea, with now only 21 per cent against recycled water in the main supply.

More than half of all sewerage collected is treated and returned to the general water supply. In Perth the rate increased to 7.4 per cent compared to 52.6 per cent in regional areas during 2010-11.

Aquifers continued to be the state’s greatest water supplier during 2010-11, with groundwater sources providing the majority (54.9 per cent) of drinking water, compared to 44.1 per cent a year earlier.

Supply from surface sources - of which dams make up the majority - fell to a five-year low of 29.4 per cent, compared to 39.4 per cent.

The decline indicates the severity of poor rainfall during the year, including the driest winter on record.

Just 13 gigalitres of rainfall flowed into dams, compared to an annual average of 54 gigalitres during 2006-10.

The declining ability to rely on dams has led Water Corporation to create a 10-year plan to “drought-proof” Perth.

The amount of drinking water sourced from desalination continued to decline, falling to 8 per cent, down from a peak of 9.3 per cent in 2008-09.

Water consumption declined across the state during 2010-11, with a 0.7 per cent fall in Perth and a 1.1 per cent drop in regional areas.

The rates follow an increase last year and usage remains well above 2006-07 levels.

The report also found the number of complaints against Water Corporation had significantly reduced while the number of connected properties increased 27,000.

Grievances such as bursts, leaks, water pressure and reliability declined by more than 50 per cent to 2.4 complaints per 1000 properties across the state.

Concerns over discolouration, taste, odour, stained washing, illness or cloudy water reduced to 3.6 per 1000 properties, with double that amount in Perth.

There were no breaches of health compliance.

However, the number of cuts in water supply soared 37 per cent to 94.3 unplanned interruptions per 1000 properties in Perth and 167.5 in other areas.

Port Hedland recorded the highest frequency of unplanned interruptions at 546 per 1000 properties.

Complaints about sewerage fell 14.8 per cent.

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